Cancer patients may one day be able to get their entire course of radiation therapy in less than a second, and researchers in Penn’s Abramson Cancer Center have taken the first steps toward making it a reality. In a report published in the International Journal of Radiation Oncology, Biology, and Physics, researchers detailed how they used proton radiation to generate the dosage needed to theoretically give a cancer patient their entire course of radiotherapy in one rapid treatment. It’s known as FLASH radiotherapy, and it’s an experimental paradigm that could represent a sea change for the world of oncology in the future. The researchers also found FLASH demonstrated the same effect on tumors as traditional photon radiation while sparing healthy tissue due to the shorter exposure time.

“This is the first time anyone has published findings that demonstrate the feasibility of using protons—rather than electrons—to generate FLASH doses, with an accelerator currently used for clinical treatments,” said the study’s co-senior author James M. Metz, director of the Roberts Proton Therapy Center and chair of radiation oncology. The co-senior authors on the study are Constantinos Koumenis, the Richard H. Chamberlain Professor of Research Oncology, and Keith A. Cengel, associate professor of radiation oncology, both in Penn’s Perelman School of Medicine.

Other research teams have generated similar doses using electrons, which do not penetrate deep enough into the body. Others have tried the approach with conventional photons, but currently available treatment devices do not have the ability to generate the necessary dosage. This study shows that with technical modifications the currently available accelerators for protons can achieve FLASH doses with the biologic effects today. 

The key was the ability to generate the dose with protons. They had to specially develop tools to measure radiation doses since the standard detectors were quickly saturated due to the high levels of radiation. The Roberts Proton Therapy Center includes a dedicated research room to run experiments like these, allowing investigators to use photon and proton radiation side-by-side just feet from the clinic. It’s one of the few facilities in the world with those unique features.

Researchers said they are already beginning to optimize how they would use this down the road for clinical trials, including taking the necessary steps to translate the ability from the research room to a clinical space, as well as designing a delivery system for FLASH in humans.